Automatic Transmission Reverse Shift Control for Noise-Free Engagement
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Solution Overview
Problem
Automatic transmissions with mechanical engaging mechanisms face issues with unusual noise or vibration when switching gear ranges during preparation processing, particularly when using a two-way clutch as a brake, which can lead to mechanical failure if switching occurs during rotation.
Innovation Solution
A control apparatus that includes a control unit to manage the engagement and release of engaging mechanisms, allowing for smooth switching by transitioning the mechanical engaging mechanism from a one-way rotation permission state to a rotation inhibition state during preparation processing, and adjusting the gear range establishment procedure based on the progress of this processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mechanical engaging mechanism is switched from the first state to the second state during rotation of the rotational element, then the reverse range can be established, but unusual noise or vibration occurs and the two-way clutch breaks
Solution Approach 1:
The control unit executes preparation processing to stop rotation of the rotational element before switching the mechanical engaging mechanism from the first state to the second state. This preliminary action of stopping rotation prevents the harmful effects of switching during rotation, eliminating unusual noise and vibration while maintaining reliability of the engaging mechanism.
2Object-affected harmful factors
If the control unit waits to start engagement of the reverse range engaging mechanism until preparation processing is complete, then noise and vibration are prevented, but responsiveness to shift range switching is delayed
Solution Approach 1:
The control unit performs preparation processing in advance to stop rotation of the rotational element before the actual switching operation. This allows the switching to occur at the optimal moment when rotation has ceased, preventing noise and vibration while minimizing the overall delay through efficient sequencing of operations.
Solution Approach 2:
The control unit monitors the rotation state of the rotational element and bases the timing of switching on this feedback information. By detecting when rotation has stopped, the control unit can precisely determine the optimal moment to switch the mechanical engaging mechanism, ensuring noise-free operation while maintaining responsive control.
3Reliability
If the control unit executes preparation processing to stop rotation before switching, then the mechanical engaging mechanism is protected from breakage, but the shift range switching takes longer to complete
Solution Approach 1:
The control unit executes preparation processing to stop rotation of the rotational element before switching the mechanical engaging mechanism. This preliminary action protects the mechanism from breakage by ensuring switching occurs only when rotation has ceased, while the control unit minimizes time loss through efficient sequencing and monitoring of the preparation process.
Data Source
AI summary
An apparatus of an automatic transmission includes a control unit controlling engagement and release of engaging mechanisms. One of the engaging mechanisms is a mechanical engaging mechanism which can be switched to a first state and a second state in which rotation of a rotational element in both directions is restricted. In a reverse range, the mechanical engaging mechanism is set in the second state. If a shift range is switched to the reverse range when the mechanical engaging mechanism is in the first state, the control unit starts engagement corresponding to the reverse range after executing preparation processing. If the shift range is switched from the reverse range to a forward range in the preparation processing, the control unit establishes a forward gear range by controlling the engaging mechanisms according to a degree of progress of the preparation processing.